Fluid flow controller



Nov. 13, 1951 A. P.:FULKERSON 2 FLUID FLOW CONTROLLER Q Filed Sept. 11,1947 2 SHEETSSHEET l IN VEN TOR. fi/RCH/EEFULKERSON BY GAMMA:

ATTORNEY.

Patented Nov. 13, i951 FLUID FLOW OONTROLLER' Archie P. Fulkerson,Louisville, Ky., assignor to Henry Vogt Machine Company, Louisville,Ky., a corporation of Kentucky Application SeptemberlI, 19%7, Serial No.773,421

2 Claims.

The present invention relates to an automatic refrigerant controller fora tube ice machine to shut off the discharge of refrigerant from thefreezing shell and trap heated gas therein in the thawin operation.

In tube ice machines there is provided a shell adapted to containing aliquid refrigerant surrounding tubes therein through which flows thewater to be frozen. At the end of the freezing operation, hotrefrigerant gas under pressure is introduced into the freezer shell todrive out the cold liquid refrigerant, and thaw the periphery of the icein the freezer tubes to free it for discharge from the machine. Theexpelled cold liquid refrigerant passes to a transfer drum or reservoir.It is necessary to maintain the pressure on the gas in the freezer inorder to realize the heat therefrom for thawing the ice, and it is alsodesirable to prevent entry of the hot refrigerant gas into the transferdrum in which the cold liquid refrigerant is held, as this wouldunnecessarily heat the liquid refrigerant. Also, as some of therefrigerant gas becomes condensed to a liquid during the thawing cycleinthe freezer, it is desirable to allow this condensed cold liquid toescape from the freezer.

It is an object of the present invention to provide a control system fora tube ice machine wherein the orifice'for, escape of liquid refrigerantfrom the freezer shell is automatically closed substantially as soon asall'the liquid're frigerant is expelled from the freezer by theinthereof by a difierential pressure timed to act upon discharge ofsubstantially all the liquid re,- frigerant from the freezer. 7

A- further object is the provision of a control apparatus in which apressure actuated valve is operated by a pilot valve which is in turncontrolled by the discharge of liquid from the freezer shell.

Another object is the provision in a tubeice machine of anapparatuswhich allows the. flow of a current of liquid therethrough, andsubstantially prevents the flow of gas therethrough.

A further object isthe provisionin' a freezer of a control apparatus inwhich a pressure actuated valve closes upon the discharge of liquidrefrigerant from the freezer, and which may be actuated to open positionby. pressure on the opposite side thereof.

In accordance with the present invention, I provide in the connectionbetween the freezer shell and the transfer drum or reservoir, a mainvalve with a-flow restriction located on one side thereof. The mainvalve, which may be of the pressure balanced type or any other suitabletype, is actuated by a pressure responsive means, the preferredarrangement being one in which the valve is normally biased to openposition, and is operated to closed position by said pressure responsivemeans. The pressure responsive means is connected to be subject tosubstantiall equal pressures under certain conditions, or to thepressure difierential across said restriction, and a control member,preferably in the form of a pilot valve, is provided to apply thepressure difsive to the level of liquid in a drain tank or cham-.-. berbelow the freezer shell and connected to the.

bottom thereof. Thus, when liquid is completely discharged from thefreezer shell into the drain tank, the change in liquid level in thechamber or drain tank actuates a float therein which in turn actuatesthe pilot valve to control the ap: plication of differential pressure tosaid pressure responsive means and close the main valve. thustrappinggaseous refrigerant in the freezer shell.

If desired, the weight of the float may be par-- tially counterbalancedbya spring or the like. During the thawing operation, some of the re-'frigerant gas is condensed to a liquid and flows into the float chamberwhere it causes actuation of the pilot valve long enough to allow theescape of the liquid'from the float chamber while trapping the gas inthe freezer. Upon completion of the thawing cycle; the liquid in thetransfer drum is placed under pressure'an'd the application of theliquidpressure in the connection between the transfer drum and the mainvalve permits the spring assisted bythe pressure responsive means of themain valve to open the valve to readmit liquid refrigerant to thefreezerfor the next freezing cycle. 1 r

m the preferred embodiment, the pressure: responsive meansv comprises apiston suitably?- 3 connected to the main valve for actuation thereof,the piston being subject on one side to the pressure of the fluid in themain valve regardless of whether the main valve is in open or closedposition and the application of pressure to the other side is controlledby the pilot valve. Any suitable type of flow restricting device may beemployed in the connection between the freezer and transfer drum, and inthe preferredembodiment, an orifice plate is used for this purpose, assuch a plate is compact and may be selected to produce the pressure dropacross the two sides thereof required for controlling the main valve.

The invention will be described in greater detail in connection with theaccompanying drawings in which there is shown a preferred the pilotReferring to the drawings, there is shown a freezer shell I, containinga suitable liquid refrigerant, such as ammonia, which surrounds aplurality of water tubes extending therethrough (not shown). A conduit 2connects the bottom of the shell I to a float tank 3, and a conduit 4leads to the inlet side of valve 5, which valve is preferably of thebalanced type, the outlet side thereof being connected by a conduit 6with a transfer storage drum or tank 1.

Referring to Figure 3, the valve 5 has an inlet passageway 8 in advanceof which is suitably located a plate -9 having a suitable orifice I Itherein. Passageway 8 connects with the transverse bore I2 havingdividing walls providing valve seats I3 and M, the latter being at theend of reduced bore I5. A valve stem I6 is longi tudinally movable inthe bore and carries suitable valve closure members I! and IB adapted toseat upon the seats I3 and I4. The plural valve closure members I1 andI8 provide a pressure balanced assembly, and it will be understoodtha-tifdesired, a single valve may be employed. The outlet passageway I9communicates with bore I2 by a port 2I, and communicates with bore I5 bya port 22, so that ports 2| and 22 and bore I2 serve to carry flow frominlet passageway 8 past the seats I3 and I4 to the outletIS.

The lower end of valve stem I8 carries a piston 23 fitting into bore I5,and the weight of the valve stem is counter-balanced by a spring 24, thecompression of which may be suitably adjusted by a threaded stem 25, soas to normally maintain the valve in open position. The pressure on theopposite sides of piston 23 is balanced by the provision of small ports26 therethrough, so that piston 23 serves to cushion the operation ofthe valve.

The upper end of valve stem I6 carries a suitable pressure responsivemeans, which in the preferred form comprises a piston 28 operating inbore I2, and the passageway 2| thus subjects the underside of piston .28to the pressure of fluid in the outlet I9 of valve. A passageway 29connects to the opposite chamber 30 of piston '28, this passageway beingconnected by a conduit 3I to passageway 32 in the float controlled valvemay be manually operated to engage stem I6 to close the valve whendesired.

From the description so far pursued, it will be apparent that the fluidpressure on piston 23 is balanced by reason of the orifices or ports 26,the valves I1 and I8 being normally held open by spring 24, and thepressure on valve closures I and I8 also is balanced. The pressure onthe lower side of piston 28 iss'ubstantially that in the outletpassageway I9 (or inlet 8, neglecting the small pressure drop throughthe valve). The pressure on the upper side of piston 28 may be varieda's'will be now explained.

Referring to Figures 1 and 2, when the float chamber 3' contains liquidsubstantially above the middle thereof, the float 35, shown in thedotted line position in Figure 1, through lever 36 holds the valve stem31' and double valve member 38 of the float controlled pilot valve, tothe left seat as shown in Figure 4, to close off communication betweenthe float chamber 3 and the passageway 32 leading to chamber 39 on theupper side of piston 28. A passageway 4| in the pilot valve is connectedby a conduit 42 (Figs. 1 and 3) to passageway 43 on the outlet side ofthe main valve 5. In this position chamber 30 is connected by conduit 3Ithrough the pilot valve and the open right seat of the pilot valve, andthrough the conduit 42 and bores 43, 2I to the downstream passageway I9,while the underside of piston 28 is connected by passage 2| to outletI9, so that in this position liquid pressure is balanced on oppositesides of piston 28. When the liquid level in chamber 3 dropssufficiently, the float 35 drops to the full line position shown inFigs. 1 and 2, and causes the double valve 38 to assume the right handposition shown in Figure 2, in which position the left seat thereof isopen. The pressure of gas in the float chamber is transmitted throughpassage 32, conduit 3I, and passage 29 to chamber 30. I At the sametime, a small flow may occur along the pilot valve stem, passage 4|,conduit 42, and passageways 43', 2I to the. outlet passageway 18 of thevalve, but by reason of the small clearance area around the pilot valvestem, this flow is small enough so as not to materially affect the.operation. The pressure in chamber 38 therefore will be substantiallythat of thegas in the float chamber 3, and the pressure onthe' undersideof piston 28 is substantially the outlet pressure in the main valve.

The operation of the apparatus now will be described. When the freezingoperation in freezer shell I is completed, the system is full of liquidrefrigerant, and hot refrigerant gas under pressure is introducedintothe shell I through a suithot gaseous refrigerant through conduit 2,float chamber 3, conduit 4, orifice II, valve 5 and conduit 6 to thetransfer drum 1.

When the liquid refrigerant is completely expelled from shell I, thelevel of liquid in'float chamber 3 drops until the float 35 movesdownwardly sufficiently? to unseat the valve member 38 from the lefthand seat and close it against.

the. right hand seat. Inthis position of the pilot val've,.the gas;pressure in the upper part of chains.

33. A threaded stem 34 may bev providedwhich her. 3 will be transmittedthroughpassageway 32,

conduit 3| and passageway 29 to the chamber 30 above the piston 28,while the pressure below piston 23 will be substantially that in outlet49. However, by reason of the flow through the orifree I i and theresulting pressure differential produced thereby on the approach anddischarge sides, the pressure in outlet passageway l9 and the pressureunder piston 28 will be materially lower than the pressure in chamber 3,so that a substantial diiferential in pressure will be developed acrossthe piston 28, with the result that the piston 28 moves the stem I5downwardly against the bias of spring 24 to close the valve members I!and I8 and stop flow of liquid refrigerant therethrough.

After the main valve closes, it is maintained closed by the pressure ofthe gaseous refrigerant applied to the top side of piston 28. Suctionpreferably is maintained on the liquid refrig erant in the transfer drumto keep the refrigerant cool by evaporation and this also serves toprevent building up of pressure on the outlet side IQ of the valve. .Anygaseous refrigerant in the freezer condensed to liquid flows intochamber 3 and if suiiicient condensate is formed to raise float 35, thepilot valve opens the right seat and closes the left seat, thus allowingthe pressures on the opposite sides of piston 28 to equalize throughconduits 3i and 42, whereupon spring 24 opens the valve. This causesflow of liquid refrigerant from conduit 4 through the valve to conduit 5and allows the liquid level in chamber 3 to again fall and again actuatefloat 35 to move valve 38 against the right hand seat to impose adifferential pressure on piston 28 to close the main valve, aspreviously described.

Upon completion of the thawing cycle and discharge of ice from thefreezer shell, suction is applied to the freezer shell by any suitableautomatic or manual arrangement and pressure is applied to the transferdrum, so that the pressure above the piston 28 drops while the pressurebelow the piston increases until it is suflicient to allow spring 24 toopen the main valve and thus allow liquid refrigerant to return to thefreezer shell for the next freezing cycle. This causes filling of thechamber 3 and raises the float therein to move the pilot valve to theleft hand seat, so that the pressures on piston 28 become balanced andvalve 5 is held open. The application of suction to the transfer drumand to the freezer as herein described ordinarily will be accomplishedautomatically by suitable solenoid controlled valves or the like, whichsuitably 6 connect the pressure and suction sides of the refrigerantcompressor to accomplish this result.

The apparatus herein illustrated and described automatically stops theflow of liquid refrigerant from the freezer shell to the storagereservoir before there is any opportunity for a substantial quantity ofthe heated refrigerant gas to enter the storage reservoir, and traps thegaseous refrigerant in the freezer shell, where it serves to release theice for discharge from the freezer. The orifice l l provides a pressuredifferential, and the float controlled pilot valve automatically appliesthe higher gas pressure to the upper side of the piston, so as toactuate the piston to close the main valve, before any substantialquantity of the gas can blow into the transfer drum.

Various modifications may be made in the invention without departingfrom the spirit or scope thereof.

Having described my invention, I claim:

1. A fluid control apparatus for a freezer comprising: a conduitconnected to said freezer for reversible flow of refrigerant; a valve insaid conduit; pressure responsive means for operating said valve; achamber connected to said conduit on one side of said valve; flowrestricting means in the conduit between the chamber and said valve; apassageway connecting said chamber to one side of the pressureresponsive means, the other side of the pressure responsive means beingconnected to the other side of said restriction; a pilot valve in saidpassageway; a duct connecting the pilot valve with said other side ofthe pressure responsive means, whereby movement of the pilot valve inone direction disconnects said chamber from said pressure responsivemeans and interconnects the two sides of the pressure responsive means;and means operated by the level of liquid in said chamber for operatingsaid pilot valve.

2. A fluid control apparatus as specified in claim 1 wherein saidpressure responsive means is a piston.

ARCHIE P. FULKERSON.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,427,600 Justus Aug. 29, 19221,866,989 Shipley July 12, 1932 2,079,412 Justus May 4, 1937

